JP2583548B2 - Radio data receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a radio data system receiver (hereinafter referred to as RD).
S receiver).

BACKGROUND ART When a broadcast station broadcasts, broadcast-related information such as information related to the program content is transmitted as data by multiplex modulation, and a desired program content can be selected on the receiving side based on the demodulated data. Radio data system (RD)
S) there.

In this radio data system, 57 kHz, which is the third harmonic of the 19 KHz stereo pilot signal outside the frequency band of the FM modulation wave, is used as a subcarrier, and the subcarrier is filtered and biphase-coded. The radio data signal is amplitude-modulated by a data signal indicating information related to the broadcast such as the content, and the amplitude-modulated subcarrier is frequency-modulated to the main carrier for broadcasting.

As is clear from FIG. 3 showing the baseband coding structure of the radio data signal, 104 bits correspond to 1 bit.
It is repeatedly multiplexed and transmitted as a group. One group is composed of four blocks each having a 26-bit configuration, and each block is composed of a 16-bit information word and a 10-bit check word. In FIG. 4, block 1 broadcasts a program recognition (PI) code representing a network, block 2 broadcasts a traffic program identification (TP) or traffic announcement identification (TA) code, and block 3 broadcasts the same program. The station frequency (AF) data of the network station in question is placed, and the block 4 contains program service information (PS) data such as a broadcast station name and a network name. In addition, each group has 4 bits of type 0 to 15 according to its contents.
There are 16 different types, and two versions of A and B are defined for each type (0 to 15). These codes are arranged in block 2. The station frequency (hereinafter abbreviated as AF) data of the network station is transmitted only in the type 0A group, and the program service name information (hereinafter abbreviated as PS) data is transmitted in the type 0A and 0B groups. Has become.

By the way, in the case of an in-vehicle receiver, the reception state of the broadcast wave being received may deteriorate as the vehicle travels.
However, when one RDS broadcast is received, the network stations that broadcast the same program as described above
Since the AF data can be obtained, the received signal level (received electric field strength) is monitored, and when this level falls below the set level, the above AF data is used to transmit to the same network station frequency where the received signal level is large. It is possible to provide a function of switching the reception frequency.

On the other hand, the TP code is arranged in the block 2 of each group and is a 1-bit code indicating whether or not it is a broadcast wave for transmitting traffic information. That is, when the TP code is logical "0", the broadcast wave does not transmit traffic information, and when the TP code is logical "1", the broadcast wave transmits traffic information. The TA code is also a one-bit code, and becomes logical "1" when transmission of traffic information is actually started, and becomes logical "0" when transmission of traffic information ends. Therefore, if a function is provided in which the RDS broadcast wave having the logic "1" is simply received and the audio output is not performed by simply receiving the RDS broadcast wave, the TA code interrupts the operation and the audio can be listened to. It is possible to automatically switch to the traffic information listening state.

Such traffic information interrupt function and the same program follow function
The RDS processing function that operates based on the data obtained from the RDS broadcast wave is valid only when receiving the RDS broadcast wave, and is valid when receiving a broadcast wave other than the RDS broadcast wave do not do. However, it is impossible for a user to easily know whether or not an RDS broadcast wave is being received simply by receiving a broadcast wave, so let's assume that the user is receiving an RDS broadcast wave and operate the RDS processing function. And other inconveniences may occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a radio capable of receiving a radio data broadcast wave and performing a radio data processing operation based on a radio data signal even when receiving a broadcast wave other than a radio data broadcast wave. It is to provide a data receiver.

A radio data receiver according to the present invention is capable of receiving a radio data broadcast wave including a radio data signal, and has a function of performing a radio data processing operation based on the radio data signal in response to a predetermined operation command. A first discriminating means for discriminating whether a broadcast wave being received when a predetermined operation command is issued is a radio data broadcast wave, and a broadcast wave being received by the first discriminating means being a radio data broadcast wave. A sweeping means for starting sweeping of a reception frequency within a reception frequency band when it is determined that the reception frequency is not a data broadcast wave;
A means for performing the radio data processing operation when the broadcast wave being received is determined to be a radio data broadcast wave by the determination means; and a broadcast wave received every time the broadcast wave is received after the start of the sweep. Second determining means for determining whether or not the received broadcast wave is a data broadcast wave; and, when the received broadcast wave is determined to be a radio data broadcast wave, stopping the sweeping by the sweeping means, Means for performing a processing operation.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1 showing an example of the configuration of an RDS receiver to which a receiving frequency selection method according to the present invention is applied, a desired station is selected by a front end 2 of an FM multiplex broadcast wave received by an antenna 1, and an intermediate frequency ( After being converted to IF), it is supplied to the FM detector 4 via the IF amplifier 3. The front end 2 obtains a local signal to the mixer 2b by a PLL synthesizer method using a PLL circuit 2a including a programmable frequency divider. The frequency division ratio of the programmable frequency divider is controlled by a controller 14 described later. In other words, the channel selection operation is performed. The detection output of the FM detector 4 is supplied to an MPX (multiplex) demodulation circuit 5, where it is separated into L (left) and R (right) channel audio signals in the case of a stereo broadcast, and reproduced via a function switching circuit 19. Audio output. The function switching circuit 19 selectively outputs an audio signal from the MPX demodulation circuit 5 or, for example, the tape player 20, and its switching control is performed by a controller.
Done by 14.

When the detection output of the FM detector 4 passes through the filter 6, a 57 KHz subcarrier amplitude-modulated by the biphase-coded data signal, that is, a radio data signal is extracted and demodulated by the PLL circuit 7. . This demodulated output is supplied to a digital (D) PLL circuit 8 and a decoder 9.
Supplied to In the D-PLL circuit 8, a clock for data demodulation is generated based on the demodulated output of the PLL circuit 7. The generated clock is supplied to the gate circuit 10. The lock detection circuit 11 detects that the D-PLL circuit 8 has locked, generates a lock detection signal, and supplies this to the gate circuit 10 to control the circuit 10 to open. The decoder 9 decodes the biphase-coded data signal, which is the demodulated output of the PLL circuit 7, in synchronization with the clock generated by the D-PLL circuit 8.

As shown in FIG. 3, the output data of the decoder 9 is in units of 104 bits consisting of four blocks each having a 26-bit configuration, and is sequentially supplied to the group and block synchronization & error detection circuit 12. The group / block synchronization & error detection circuit 12 synchronizes the group with the block based on the 10-bit offset word assigned to the 10-bit check word of each block, and 16-bit information based on the check word. Word error detection is performed. Then, the error-detected data is supplied to the controller 14 after the error is corrected by the error correction circuit 13 at the next stage.

The controller 14 is constituted by a microcomputer, and the code information of each block in the radio data sequentially inputted in the group unit, that is, the radio data information (the PI data and the AF data described above) related to the program contents of the broadcasting station currently being received. , PS data, etc.) and store them in the memory 15, and determine the frequency division ratio of the programmable frequency divider of the PLL circuit 2 a constituting a part of the front end 2 based on a channel selection command from the operation unit 16. The tuning operation is performed by controlling the reception frequency data value.

Further, a level detection circuit 17 for detecting a reception signal level (electric field strength) based on the IF signal level in the IF amplifier 3.
And a station detection circuit for outputting a station detection signal assuming that a broadcast wave has been received when the IF signal level in the IF amplifier 3 is equal to or higher than a predetermined level and the detection output of so-called S-curve characteristics in the FM detector 4 is within a predetermined level range. The station detection signal output from the station detection circuit 18 and the received signal level detected by the level detection circuit 17 are supplied to the controller 14.

The memory 15 includes a nonvolatile RAM (not shown) in which data such as reception frequency data, a PI code, and AF data are written, and a ROM in which programs and data are written in advance.
(Not shown).

Next, the procedure of the control method according to the present invention executed by the processor of the controller 14 will be described with reference to the flowchart shown in FIG.

When the processor is receiving a broadcast,
It is determined whether or not 16 identical program follow buttons (not shown) have been operated (step 51). If there is an operation of the same program follow button 1 is set to the flag F _N (step
52), it is determined whether or not the received broadcast wave is an RDS broadcast wave (step 53). If the received broadcast wave is an RDS broadcast wave, this means that data has been output from the error correction circuit 13. If data can be obtained from the output of the error correction circuit 13, the processing of this routine ends. If no data is obtained from the error correction circuit 13 and the reception of the RDS broadcast wave is not being performed, the process proceeds to step 59 described below to set the sweep mode.

On the other hand, if the same program tracking button has not been operated in step 51, it is determined whether or not a TA interrupt button (not shown) on the operation unit 16 has been operated (step 54). TA
If the interrupt button is operated, "1" is set to the flag F _D (step 55), for example, the function switching circuit 19 so as to select the audio signal from the tape player 20
(Step 56).
Next, it is determined whether or not the received broadcast wave is an RDS broadcast wave (step 57). If the received broadcast wave is not an RDS broadcast wave, the process proceeds to step 59. If the received broadcast wave is an RDS broadcast wave, it is determined whether or not the content of the TP code in the data obtained from the output of the error correction circuit 13 is logic "1" (step 58). If the TP code is logical "1", it means that an RDS broadcast wave for broadcasting traffic information has been received, and the processing of this routine ends. If the TP code is logical "0", the step is not an RDS broadcast wave for broadcasting traffic information.
Move to

In step 59, the reception frequency data value supplied from the controller 14 to the PLL circuit 2a of the front end 2 is changed. Thereafter, it is determined whether or not a predetermined time T has elapsed since the reception frequency data value was changed (step 6).
0) If the predetermined time T has elapsed, it is determined whether or not a station detection signal has been generated (step 61). The predetermined time T
Is a time slightly larger than the time from when the reception frequency data value is changed to when the station detection signal by the broadcast wave is obtained when the broadcast wave can be received. When the reception frequency data value changes, the frequency division ratio of the frequency divider of the PLL circuit 2a changes in a predetermined step, and the reception frequency increases by, for example, 100 KHz. If a broadcast wave cannot be received at this new reception frequency, no station detection signal is generated, so the flow returns to step 59 to change the reception frequency again. Therefore, when the broadcast wave cannot be received, the reception frequency changes every predetermined time T. On the other hand, when a new broadcast wave is received, the station detection circuit 18 generates a station detection signal when the IF signal level becomes equal to or higher than a predetermined level and the FM detection output of the S curve characteristic is within a predetermined level range. When the station detection signal is generated, it is determined whether or not the received broadcast wave is an RDS broadcast wave (step 62). If the received broadcast wave is not an RDS broadcast wave, the flow returns to step 59 to change the received frequency again. If the received broadcast wave is a RDS broadcasting wave, the flag F _D is determined whether equal to "1" (step 63). TA if F _D = 0
The interrupt button is not operated and the current reception frequency data value is held (step 65), and the sweep mode ends.
If F _D = 1, the TA interrupt button is operated, so it is determined whether or not the content of the TP code of the data obtained from the output of the error correction circuit 13 is logic “1” (step 6).
Four). If the TP code is logical "0", it is not an RDS broadcast wave for broadcasting traffic information, so the process returns to step 59 to change the reception frequency again. If the TP code is logic "1", it means that an RDS broadcast wave for broadcasting traffic information has been received, and the flow advances to step 65 to hold the current reception frequency data value and end the sweep mode. After the end of the sweep mode, the PI code,
Write input data such as PS data to the memory 15.

Thus, when the same program follow button or the TA interrupt button is operated, if a broadcast wave other than the RDS broadcast wave is being received, the sweep mode is set, and if the RDS broadcast wave is received, the sweep mode is terminated and the RDS broadcast wave is terminated. Is maintained. Therefore, the RDS broadcast receiving state in which the same program follow-up function and the traffic information interrupt function can be operated.

In the above-described embodiment, the same program follow-up function and the traffic information interrupt function have been described as the RDS processing functions. However, the present invention is not limited to this. For example, an auto-preset function of the frequency (ON) data of another network station may be used. The present invention can be applied to the RDS processing function.

Effects of the Invention As described above, according to the radio data receiver of the present invention, when a predetermined operation command for performing a radio data processing operation is received during reception of a broadcast wave other than a radio data broadcast wave, the radio data receiver falls within the reception frequency band. Of the received frequency, and when the radio data broadcast wave is received after the start of the sweep, the sweep is stopped and the radio data processing operation is actually performed from the radio data broadcast reception state. Therefore,
Even during reception of broadcast waves other than radio data broadcast waves, radio data broadcast reception can be achieved by simple operations such as button operation and radio data such as frequency data necessary for radio data processing operations can be obtained. Processing operations can be reliably executed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an RDS receiver according to the present invention, FIG. 2 is a flowchart showing a control procedure executed by a processor in a controller of FIG. 1, and FIG. 3 is baseband coding of a radio data signal. FIG. 4 is a diagram showing a structure, and FIG. 4 is a diagram showing a format of a type OA group. Description of main parts 2... Front end, 4... FM detector 5... Multiplex demodulation circuit 8... Digital PLL circuit 9... Decoder, 14.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-134130 (JP, A) Nikkei Electronics August 24, 1987, pp. 202-217

Claims (3)

(57) [Claims] A radio data receiver capable of receiving a radio data broadcast wave including a radio data signal and having a function of performing a radio data processing operation based on the radio data signal in response to a predetermined operation command. A first determining unit that determines whether a broadcast wave being received when the predetermined operation command is generated is a radio data broadcast wave; and a broadcast wave being received by the first determining unit is a radio data broadcast. When it is determined that the broadcast wave is not a wave, a sweeping unit that starts sweeping a reception frequency within a reception frequency band; and when the broadcast wave being received by the first determination unit is determined to be a radio data broadcast wave, Means for performing the radio data processing operation; and second determination means for determining whether or not the received broadcast wave is a radio data broadcast wave every time a broadcast wave is received after the start of the sweeping. And means for performing the radio data processing operation by stopping the sweep by the sweeping means when the received broadcast wave is determined to be a radio data broadcast wave by the second determination means. And radio data receiver. 2. The radio program processing operation according to claim 1, wherein the radio program processing automatically selects another radio data broadcasting station which is broadcasting the same program when the reception condition of the broadcast wave being received deteriorates. 2. The radio data receiver according to claim 1, wherein the predetermined operation command is a same program following command for starting the same program following operation. 3. The radio data processing operation interrupts a radio data broadcast wave audio output until traffic information is transmitted, waits for reception, and makes the audio output audible when traffic information is transmitted. Action
2. The traffic information interrupt command for starting a traffic information interrupt processing operation, wherein the predetermined operation command is a traffic information interrupt command.
Radio data receiver as described.